New York (CNN) -- A federal jury began deliberations Monday in the case of a man accused -- with two others -- of plotting to bomb New York's subway system.
Prosecutors say Adis Medunjanin, a Bosnian-born American, conspired with admitted terrorists Najubullah Zazi and Zarein Ahmedzay in the terrorist plot planned, but never executed, in 2009.
In closing arguments late last week at a federal court in Brooklyn, Assistant U.S. Attorney Berit Berger said that Medunjanin was willing "to strap a suicide bomb to himself, walk into a New York City subway and blow it up."
Berger told jurors that al Qaeda leaders assigned the mission to Medunjanin in 2008, while he was in Pakistan's tribal belt with two high school friends, Najibullah Zazi and Zarein Ahmedzay.
Medunjanin's attorney Robert Gottlieb denied the prosecution's account in his own closing arguments, insisting his client traveled to Pakistan "not to join al Qaeda, but to join the Taliban in fighting foreign troops in Afghanistan."
Gottlieb said Medunjanin wanted to join the Taliban to stand up for Muslims and defend the Muslim religion. He called all three young men, including Zazi and Ahmedzay, "immature, naive and clueless" when they set out.
"They wanted to fulfill some romantic version of jihad," Gottlieb said.
Upon their return to the United States, prosecutors contend that Medunjanin and his two friends hatched a plan to rig backpacks with explosives and blow them up.
But Gottlieb denies his client had a role in such a bomb plot.
Medunjanin has pleaded not guilty to charges that include conspiring to use weapons of mass destruction and conspiring to provide material support to al Qaeda. He faces life in prison if convicted.
Co-conspirators Zazi, an immigrant from Pakistan, and Ahmedzay, an immigrant from Afghanistan, have pleaded guilty to planning the attack with him and are awaiting sentencing.
Both men have cooperated with the government and testified at Medunjanin's trial.